Hi so I have had my betta since November and it isnt until now that I realized I need to be doing so much more for him. So I have several questions please help me

Should I get a tank with a filter?
-would that make it so I have to change the water less often?
-will that make it easier for him to breathe?
-is it truly necessary? (Im a broke college kid but will do what I need to)

Does he need a light at night?

How often should I really change the water?

Should I have a live plant?

How much space should I give him to swim?

Thats pretty much all I can think of for now. All answers and advice are greatly appreciated!

It's not necessary to get a filter (as I am also a broke college kid, lol). Just do weekly water changes. :)
He doesn't need a light on at night either. But he does need at least a 2 gal. tank, and a heater - heated to 78-80 F.
What's your current tank size? It depends how small/big it is on how many water changed you need to do. Live plants are also no needed. I like to use the wal-mart plants that are sold as bulbs- they grow into pretty hardy plants. Not sure what they are though :/

Welcome to the forum.....and to the wonderful world of Betta keeping.....

In response to your PM....

The 1gal is fine and you don't have to have a filter...not needed and sometimes on smaller tanks can be the cause of stress and fin issues

Getting a bigger tank is good-some Bettas thrive in bigger tanks and other don't...this can vary from fish to fish....

You also need a thermometer to monitor the water temp and maintain it in the 76-80F range...again this can vary with Bettas....some like it warmer when other like it cooler....you may or may not need a heater...but its a good idea to have one on hand....

In a 1gal unfiltered tank-water changes of twice weekly...1-50% and 1-100% should maintain water quality...provided that you don't overfeed or leave left over food in the tank....

Live plants-make sure you are getting true aquatic plants....often the plants sold in tubes are not and will rot and die polluting the water causing problems...correct lights and photoperiod are also important for successful plant keeping....kelvin of 6500k lights on for 10h/day

Lights off at night...fish need a day-night cycle to rest since they don't have eyelids.....

With water changes it is important to try and keep the water temp within a couple of degrees between new and old water to prevent temp shock and Always use dechlorinator with any new water added to the fish...dose for the full volume of the tank not just the replacement water.....

Feeding...small frequent meals....remember their stomach is about the size of their eye....overfeeding can kill the Betta.....

Right now...I would start him on daily 50% water changes for 2 days then 100% and see if this will perk him up....check the temp and get that in the 76-80F and hold food for 3 days...then feed small meals 2-3 times a day......fast one day a week....if he doesn't improve or he start to have buoyancy problems....let me know and I will give you the Epsom salt treatment...

Also-you need aquarium salt and Epsom salt on hand...and if you have access to native oak leaf....have some of these on hand too or IAL and a clean 1gal jug with a lid...I use milk jugs but water jugs or OJ jugs will work too.....

If I forgot something...just ask......lots of good fish keeper ready and willing to help you out......